Forest Succession in Tropical Hardwood Hammocks of the Florida Keys: Effects of Direct Mortality from Hurricane Andrew¹

Abstract

A tree species replacement sequence for dry broadleaved forests (tropical hardwood hammocks) in the upper Florida Keys was inferred from species abundances in stands abandoned from agriculture or other anthropogenic acitivities at different times in the past. Stands were sampled soon after Hurricane Andrew, with live and hurricane‐killed trees recorded separately; thus it was also possible to assess the immediate effect of Hurricane Andrew on stand successional status. We used weighted averaging regression to calculate successional age optima and tolerances for all species, based on the species composition of the pre‐hurricane stands. Then we used weighted averaging calibration to calculate and compare inferred successional ages for stands based on (1) the species composition of the pre‐hurricane stands and (2) the hurricane‐killed species assemblages. Species characteristic of the earliest stages of post‐agricultural stand development remains a significant component of the forest for many years, but are gradually replaced by taxa not present, even as seedlings, during the first few decades. This compositional sequence of a century or more is characterized by the replacement of deciduous by evergreen species, which is hypothesized to be driven by increasing moisture storage capacity in the young organic soils. Mortality from Hurricane Andrew was concentrated among early‐successional species, thus tending to amplify the long‐term trend in species composition.

Predicting and quantifying the structure of tropical dry forests in South Florida and the Neotropics using spaceborne imagery

“…There are a high number of stems with a low basal area in young or disturbed forests. As forests mature, density generally decreases as the basal area and canopy height increases until an equilibrium is achieved (Brokaw & Walker, 1991;Ross et al, 2001;Kennard, 2002). Once these forests have matured, there is no relationship between density and basal area (Kennard, 2002).…”

“…Study sites in Florida were divided into two classes based on the track of Hurricane Andrew that struck the northern region of the study area on 24 August 1992 to identify significant differences in forest structure 10 years after hurricane disturbance. These classes included (1) study sites within the northern and southern extent of the eye wall of Hurricane Andrew, and (2) study sites outside the eye wall of Hurricane Andrew that experienced minimal damage (Ross et al ., 2001).…”

Hurricane Impacts on Key Deer in the Florida Keys

“…Reports indicate that hurricanes or tropical storms might have a negative impact on the Key deer population (Klimstra et al 1974, Silvy 1975, Seal and Lacy 1990, which currently numbers about 482 on BPK (406) and NNK (76;Lopez 2001). Hurricanes have been a major natural disturbance affecting coastal areas in the United States, particularly in the Caribbean islands (Boose et al 1994, Ross et al 2000. The role of hurricanes on the flora and fauna of the Florida Keys is of interest due to the relatively high frequency of tropical stonn occurrences and the low land elevations «3 m), that make these islands susceptible to stonn surges (Folk 1991, Ross et al 2000.…”

“…Hurricanes have been a major natural disturbance affecting coastal areas in the United States, particularly in the Caribbean islands (Boose et al 1994, Ross et al 2000. The role of hurricanes on the flora and fauna of the Florida Keys is of interest due to the relatively high frequency of tropical stonn occurrences and the low land elevations «3 m), that make these islands susceptible to stonn surges (Folk 1991, Ross et al 2000. At the landscape level, hurricanes have the potential to reshape shorelines, cause extensive damage to vegetation in forested areas, and change hydrological properties (Boose et al 1994, Ross et al 2000.…”

“…The role of hurricanes on the flora and fauna of the Florida Keys is of interest due to the relatively high frequency of tropical stonn occurrences and the low land elevations «3 m), that make these islands susceptible to stonn surges (Folk 1991, Ross et al 2000. At the landscape level, hurricanes have the potential to reshape shorelines, cause extensive damage to vegetation in forested areas, and change hydrological properties (Boose et al 1994, Ross et al 2000. Potential impacts of hurricanes on deer populations include direct mortality and/or a reduction in herd productivity (Folk 1991, Labisky et al 1999.…”